The invention relates to a sealing system for sealing off a conduit passage in a building component, in particular for sealing off a pipe line passage in a building component. The sealing system comprises at least one sealing means for sealing off the passage and at least two support members for holding the sealing means, wherein each support member has a fastening section for attachment of the support member to the building component. The invention further relates to a support member with a first member configured as a fastening section for fastening the support member to a building component and at least a second member configured as a sleeve segment for attaching an object, in particular a sealing means to the building component.